1. Field of the Invention
This invention relates to a screen for an aquarium tank and, more particularly, to a screen which is disposed in an aquarium tank for enhancing the appearance of the tank interior.
2. Description of the Prior Art
FIG. 5 shows a prior art aquarium tank. As shown, the tank comprises a tank body 51, over which a filter unit 52 is disposed. The filter unit 52 has a base frame 54 which is placed on an upper frame 53 of the tank body. A filter tank 55 and a pump mechanism 56 are mounted on the base frame 54. A filter chamber 57 and a float chamber 58 are formed in the filter tank 55. Water is drawn from the tank by the pump mechanism 56 and supplied to and filtered through a filter material 59 in the filter chamber 57, and the filtered water is returned through the float chamber 58 and down through a return pipe 60 into the tank. In the filter chamber 57, a drain board 61 is laid so as to be spaced apart from the bottom of the chamber. The filter material 59 is placed on the drain board 61. Over the filter material 59, a distributing trough 62 exends in the longitudinal direction (to the left and right in FIG. 5) of the filter chamber 57. Water discharged from a discharge nozzle 63a of a delivery pipe 63 of the pump mechanism 56 first flows into the distributing trough 62 to be distributed uniformly over the filter material 59 through many distributing holes (not shown) formed in the bottom of the trough. The filtered water from the filter material 59 flows through a passage formed between the drain board 61 and the bottom of the chamber 57 to enter the float chamber 58 and thence return through the return pipe 60 and an outlet 64 into the tank.
The pump mechanism 56, which pumps water from the tank body 51 to the filtering section (i.e., the filter chamber 57 with the filter material 59 placed therein) comprises a motor 65 mounted in the filter unit 52, a cylindrical member 66 through which a motor shaft (not shown) extends downward from the motor 65 into the interior of the tank body 51, an intermediate frame 67 provided at the lower end of the cylindrical member 66 and rotatably accommodating a vane (not shown) mounted at the lower end of the motor shaft, an extension pipe 68 extending from the intermediate frame 67 to communicate with the delivery pipe 63 and having its lower end open in the tank interior, and a strainer 69 mounted on the lower end of the pipe 68 and serving to prevent comparatively large particles from being drawn into the pipe 68. The water conducting section of the pump mechanism 56, which comprises the delivery pipe 63, the cylindrical member 66, the intermediate frame 67, the extension pipe 68, the strainer 69, etc., extends from the underside of the case of the filter unit 52 into the tank body 51. A heater 70 for regulating the temperature of the water in the tank is disposed at the bottom of the tank body 51 (for instance, on gravel spread on the tank bottom).
In the prior art aquarium tank described above, the water conducting section of the pump mechanism extends down from the filter unit case underside and therefore spoils the appearance of the tank interior. This detracts from the observer's aesthetic impression of the aquarium tank and the fish and plants kept in it.